Integrated electric motor and fluid pump

ABSTRACT

A fluid pump including an integrated pumping section and motor section may be achieved by a variety of techniques. In certain aspects, a fluid pump may include an integrated pumping section, motor section, and a control section that share structural components in order to reduce the structural material required for the complete device while simultaneously utilizing the integrated motor controller to enable the pump to operate at varying speeds other than the synchronous electrical power frequency that powers the device.

RELATED APPLICATIONS

This application claims priority from U.S. Patent Application No. 62/368,509, filed Jul. 29, 2016, which is herein incorporated by reference in its entirety.

TECHNICAL FIELD

The present invention is in the field of fluid pumps driven by an electrical motor, and in particular, to fluid pumps that utilize the power provided by the electric motor to add energy to the fluid in the form of increased fluid pressure and/or fluid flow velocity.

BACKGROUND

Fluid pumps commonly have a discrete pumping section that is then coupled directly to a separate electric motor by a shaft coupling device which transmits the torque and rotation of the electric motor to the impeller of the pump to impart energy into the fluid being pumped. Fluid pumps can have many configurations, some of which are centrifugal flow pumps, axial flow pumps, and pitot tube pumps, which all relate to the invention.

In the past, the pump was designed, engineered, and built as a standalone, discrete component with an input shaft directly connected to the pump impeller. The electric motor was a separate, discrete component that was connected to the pump by way of a coupling mechanism in order for the electric motor to drive the pump's impeller. The pump's impeller may or may not have had one or more bearings that support the rotational loads of the impeller. The electric motor also may or may not have had a set of bearings that support the rotational loads of the electric motor's rotor. In some cases, the pump impeller was attached directly to the shaft of the electric motor and utilized the bearings of the electric motor's rotor to support the rotational loads of both the electric motor's rotor and the pump's impeller. This is the most common configuration of pump and motor found in industry practice today for low power pumps. High power pumps utilize separate bearings for the pump and electric motor respectively.

In the fluid pump industry, there are classifications of pumps such as coupled pumps and close coupled pumps. The present disclosure is intended to create a new classification wherein the pump is an integral component of the electric motor. Designing and manufacturing pumps and motors to function as standalone components requires a redundancy of materials in the structures of each component as well as numerous other components that can be eliminated when a pump and motor are designed and manufactured into one cohesive unit.

Presently in the industry, pumps are typically operated at the synchronous speeds of the AC induction motor that is driving the pump. The specific speed of those pumps depends on the number of poles in the AC induction motor, with those typically being 2, 4, 6, 8, 10 and 12 pole motors. The speeds for these number of pole motors, utilizing a 60 Hz electrical frequency, are 3600, 1800, 1200, 900, 720, and 600 RPM, respectively. The speed of the electrical induction motor is determined by the power supply frequency and the number of poles in the motor winding, which is described by the following equation:

n=f(2/p)60

where

n=shaft rotation speed (rev/min, rpm)

f=frequency (Hz, cycles/sec, 1/s)

p=number of poles

In order to operate a conventional pump at speeds other than those tied to the electrical frequency delivered to the pump motor, a separate motor controller is required, which is typically referred to as a Variable Frequency Drive (VFD). Adding a VFD to a pump and being able to control the pump at higher speeds enables a smaller physical size pump to provide the same pressure and head as a slower speed larger physical sized pump. Additionally, the efficiency of the pump can be improved by utilizing a VFD in matching the speed of the pump to the required pressure and head desired for the application. Presently, the cost of adding a VFD to control pumps is prohibitively expensive for the low power pump market and difficult to justify in the high power pump market.

SUMMARY OF INVENTION

In particular aspects, the present disclosure relates to using the structural component of the fluid pump housing, the volute, as the front structural bearing housing of the electric motor. The electric motor shaft, bearing, and seal function as the shaft, impeller support bearing, and seal of the fluid pump. The integrated electric motor fluid pump embodied herein is of a high speed design and may utilize an integrated electric motor control located inside the motor/pump housing. The motor section may, for example, use a switched-reluctance stator.

In certain implementations, an integrated electric motor and fluid pump may include a pumping section, a control section, and motor section, and an outer housing. The motor section may include a stator, a rotor, and a shaft, the shaft located inside the rotor and rotated thereby. The outer housing may at least partially surround the motor section and be coupled to and support the pumping section and the control section.

In certain implementations, wherein the electric motor section may further include a bearing that supports the shaft. The bearing may be configured to support the pumping section.

In some implementations, the control section may include a controller that adjusts the speed of the pump to vary with respect to accommodate and respond dynamically to the load required by the pump.

In particular implementations, the housing may be composed of thermoplastics. The housing may include integrated non-thermoplastic elements that function as heatsink elements to allow thermal cooling of the motor pump components.

In certain implementations, the shaft may include a hollow center to convey the fluid being pumped into the pumping section. The pumping section may be a centrifugal, axial, or pitot-tube type pump in these implementations. The shaft may include an integral axial flow impeller to convey the fluid being pumped to the pumping section. Additionally, the pumping section may include a fluid volume housing that is an integral with of the shaft such that the fluid volume is rotate thereby or the pumping section may include a pitot tube that is integral with the shaft such that the pitot tube is rotated thereby.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a line drawing illustrating an example embodiment in accordance with one aspect of the present invention showing an integrated electric motor, centrifugal pump, and controller assembly.

FIG. 2 is a line drawing illustrating a cross-section of the example embodiment of the integrated electric motor, centrifugal pump, and controller assembly.

FIG. 2A is a line drawing illustrating a cross-section of another example embodiment of an integrated electric motor, centrifugal pump, and controller assembly.

FIG. 3 is a line drawing illustrating a simplified cross-sectional view of an example 4-phase, radial flux, switched reluctance motor.

FIG. 4 is a line drawing illustrating a cross-section of another example integrated electric motor, centrifugal pump, and controller assembly.

FIG. 5 is a line drawing illustrating an example embodiment in accordance with one aspect of the present invention showing a hollow shaft with through shaft fed impeller.

FIG. 5A is a line drawing illustrating another example embodiment in accordance with one aspect of the present invention showing a hollow shaft with through shaft fed impeller.

FIG. 6 is a line drawing illustrating an example embodiment in accordance with one aspect of the present invention showing a hollow shaft with integral axial flow impeller.

FIG. 6A is a line drawing illustrating an additional example embodiment in accordance with one aspect of the present invention showing a hollow shaft with integral axial flow impeller.

FIG. 7 is a line drawing illustrating a cross-section of an example embodiment in accordance with yet another aspect of the present invention showing a hollow shaft with pitot tube pump.

FIG. 7A is a line drawing illustrating a cross-section of another example embodiment in accordance with yet another aspect of the present invention showing a hollow shaft with pitot tube pump.

FIG. 7B is a line drawing illustrating a cross-section of yet another example embodiment in accordance with yet another aspect of the present invention showing a hollow shaft with pitot tube pump.

DETAILED DESCRIPTION OF THE FIGURES

FIGS. 1-2 illustrate an example integrated electrical motor and fluid pump 100. Among other things, pump 100 includes a pumping section 120, a motor section 130, and a control section 140 that are integrated together. Pump 100 also includes a housing 110 that at least partially surrounds motor section 130.

Housing 110 protects motor section 130 and prevents users from accessing dangerous components of motor section 130 during operation. Additionally, pumping section 120 and controller 140 couple to and are supported by housing 110. Housing 110 may, for example, be made of plastic (e.g., thermoplastic) or any other appropriate material.

As illustrated, pumping section 120 includes an inlet 122, an outlet 124, and an impeller 126 and operates according to centrifugal flow techniques. In other embodiments, pump 120 may operate by other techniques (e.g., axial flow or pitot tube).

Motor section 130 includes a rotor 132, a stator 134, a shaft 136, and bearings 138. In the illustrated embodiment, rotor 132 and stator 134 each include a number of poles such that the rotor is driven by magnetic flux induced in the stator's poles. That is, the rotor's series of poles are controllably attracted to the stator's series of poles that surround the rotor. In particular, implementations, rotor 132 is driven by radial-flux switched reluctance techniques. In other embodiments, rotor 132 may be driven by other techniques (e.g., axial flux switched reluctance or transverse flux switched reluctance, or synchronous, whether single-phase or poly-phase). Shaft 136 is coupled to the interior of rotor and is driven by the rotation thereof. Shaft 136 may be hollow or solid. At either end of shaft 136 are bearings 138 that support the shaft longitudinally and allow it to rotate with minimal friction.

FIG. 3 shows a simplified cross-sectional view of an example 4-phase, radial flux, switched reluctance motor section 130. In particular, motor section 130 has a rotor 140 located inside a stator 150. The stator 150 has eight poles 150, and the rotor 140 has six poles 142. Each pole 152 includes a conductor 154 wrapped therearound to supply electrical current to induce a magnetic field in the pole. As the nomenclature implies, the stator 150 is held against rotation while the rotor 140 rotates around a central rotatable shaft (not shown) that extends along the central axis of the electric machine. The stator core of an electrical machine is most commonly made by forming a circular or square lamination with a circular area for the rotor to turn around and then stacking those laminations to form a monolithic core structure. The manufacturing of the stator laminations typically involves cutting out the shapes of the stator laminations from a single lamination sheet. Other poly phase or single phase (e.g., where the number of poles between the stator and rotor match) machines may be used.

As can be seen in FIG. 2, shaft 138 directly couples to impeller 126 of pumping section 120. Thus, bearing 138 b also serves as the bearing for pumping section 120.

In this implementation, control section 140 is coupled to the opposite end of pump 100 from pumping section 120. In other implementations, the control section may be located on the front, side, top, and/or bottom of the motor section and/or on the pumping section. Control section 140 may, for example, include power semi-conductors, gate drivers, and a controller (e.g., a microprocessor, a microcontroller, a field-programmable gate array, or an application specific integrated circuit). In this implementation, control section 140 includes a control board 142 upon which the controller is mounted.

Control section 140 is responsible for controlling the supply of current to the coils in the motor section 130. As part of this, controller 140 may include a sensor (not viewable here) to determine the position of shaft 136. Appropriate sensors may operate by electronic (e.g., Hall effect), optical (e.g., optical disks), or magnetic (e.g., reluctance or inductance sensing) techniques. Control section 140 allows the motor section 130 to work at variable speeds by adjusting the time that the stator poles are active and the amount of current supplied thereto. Also, control section 140 allows motor to dynamically adjust to the load required by the pump (e.g., by increasing rotation speed and/or torque). Control section 140 may also convert AC power to DC power.

As part of its adjustments, control section 140 may include and/or receive input from one or more sensors (e.g., pressure, flow, and/or temperature sensors). The control section may use relay the data from these sensors to a main controller, which may optimize the operation of a system in which the pump resides.

In certain implementations, control section 140 may include wireless communication capabilities (e.g., Ethernet, Bluetooth, or ZigBee). This may allow the pump to wirelessly communicate data with other pumps and industrial systems in order to increase the efficiency of the home or industrial process plant as a whole.

In operation, the sensor may provide an indication of the rotational position of the rotor and shaft 136 to the control section 140. When a pole of the rotor is approaching a pole of the stator (e.g., when a rotor pole is more than half way between two stator poles), the stator poles may be activated (assuming a single phase system) to attract the rotor poles. The activation of the stator poles produces a magnetic flux through the stator poles that causes the poles of the stator and the rotor to want to align, thereby moving the rotor poles towards the stator poles and a position in which the reluctance of the magnetic circuit is reduced to a minimum. As the rotor pole moves closer to being aligned with the stator pole, which may be the point at which the reluctance is a minimum, the current to the stator poles may be switched off to allow the rotor poles to move past the stator poles and continue toward the next stator pole turn-on position. In certain implementations of the present invention, the fluid being pumped may be used to thermally cool the stator and electric motor controller in order to improve the overall efficiency of the device.

Pump 100 has a variety of advantages. For example, it is smaller on a power basis than other pumps, making it easier to ship and install. The pump has an intelligent controller built-in, which enables the pump to actively adapt to changing pumping conditions of the fluid being pumped. The integral controller may also include a means of wireless communication that enables the pump to communicate data with other pumps and industrial systems in order to increase the efficiency of the home or industrial process plant as a whole. Additionally, pump 100 allows for variable speed operation. Thus, the pump may be configured for efficient operation after being manufactured.

Additionally, by integrating the pump, motor, and controller, the structural components may be shared, which reduces the amount of material for the completed device, reduces manufacturing costs of the collective unit, and improves the efficiency of the collective unit. Moreover, sharing the structural materials allows the device structure to be made of less costly materials, such as thermoplastics. Using materials such as thermoplastics also allows easier end-of-life recyclability of the device.

FIG. 2A illustrates another example integrated electric motor and pump 100′ in accordance with the present invention. Similar to pump 100, pump 100′ includes a pumping section 120, a motor section 130, and a control section 140 that are integrated together. Pump 100′ also includes a housing 110 that at least partially surrounds motor section 130.

Housing 110 protects motor section 130 and prevents users from accessing dangerous components of motor section 130 during operation. Additionally, pumping section 120 and control section 140 couple to and are supported by housing 110. Housing 110 may, for example, be made of plastic (e.g., thermoplastic) or any other appropriate material.

As illustrated, pumping section 120 includes an inlet 122, an outlet 124, and an impeller 126 and operates according to centrifugal flow techniques. In other embodiments, pump 120 may operate by other techniques (e.g., axial flow or pitot tube). Pumping section 120 also includes a mechanical seal 128 to prevent the pump fluid from leaking into motor section 130.

Motor section 130 includes a rotor 132, a stator 134, a shaft 136, and bearings 138. In the illustrated embodiment, rotor 132 and stator 134 each include a number of poles such that rotor 132 is driven by magnetic flux induced in the stator's poles. That is, the rotor's series of poles are controllably attracted to the stator's series of poles that surround the rotor. In particular, implementations, rotor 132 is driven by radial-flux switched reluctance techniques. In other embodiments, rotor 132 may be driven by other techniques (e.g., axial flux switched reluctance or transverse flux switched reluctance, or synchronous, whether single-phase or poly-phase). Shaft 136 is coupled to the interior of rotor and is driven by the rotation thereof. Shaft 136 may be hollow or solid. At either end of shaft 136 are bearings 138 that support the shaft longitudinally and allow it to rotate with minimal friction.

In this implementation, control section 140 is split into two parts, 140 a, 140 b. Part 140 a is coupled to the opposite end of pump 100 from pumping section 120, and part 140 b is coupled to the top of the housing 110. Control section 140 may, for example, include power semi-conductors, gate drivers, and a controller (e.g., a microprocessor, a microcontroller, a field-programmable gate array, or an application specific integrated circuit). In this implementation, control section 140 includes a board (e.g., a printed circuit board) upon which the controller is mounted.

Control section 140 is responsible for controlling the supply of current to the coils in the motor section 130. As part of this, control section 140 may include a sensor (not viewable here) to determine the position of shaft 136. Appropriate sensors may operate by electronic (e.g., Hall effect), optical (e.g., optical disks), or magnetic (e.g., reluctance or inductance sensing) techniques. Control section 140 allows the motor section 130 to work at variable speeds by adjusting the time that the stator poles are active and the amount of current supplied thereto. Control section 140 may also convert AC power to DC power.

In certain implementations, control section 140 may include wireless communication capabilities (e.g., Ethernet, Bluetooth, or ZigBee). This may allow the pump to wirelessly communicate data with other pumps and industrial systems in order to increase the efficiency of the home or industrial process plant as a whole.

FIG. 4 illustrates an example integrated pump 200 in accordance with another aspect of the present invention. Similar to pump 100, pump 200 includes a pumping section 220 and a motor section 230 incorporated by a housing 210. However, in this embodiment, housing 210 includes a number of heat sink elements 212 incorporated therein by way of insert molding. Heat sink elements 212 may, for example, be made of a thermally conductive material such as aluminum. Incorporating heat sink elements 212 in housing 210 allows the power semi-conductors and/or other electronic components to transmit the heat generated from the current switching process to the ambient environment around the pump. In another embodiment of the present invention, the heat sink elements could be liquid cooled, either by a separate cooling fluid from the fluid being pumped or by a directed partial flow of the fluid being pumped to the heat sink elements.

FIG. 5 illustrates an example integrated pump 300 in accordance with another aspect of the present invention. Similar to pump 100, pump 300 includes a pumping section 320, a motor section 330, a control section 340, and an integrating housing 310. However, in this embodiment, motor 330 includes a shaft 332 that is hollow, allowing fluid to enter pumping section 320 from the motor side. In this embodiment, pumping section 320 operates by centrifugal techniques, but pumping section 320 may utilize for other techniques (e.g., pitot-tube, with a pitot tube type impeller replacing the centrifugal impeller and an additional fluid inlet on the closed volute housing).

FIG. 5A illustrates another example integrated pump 300′ in accordance with yet another aspect of the present invention. Similar to pump 300, pump 300′ includes a pumping section 320, a motor section 330, a control section 340, and an integrating housing 310. Additionally, motor 330 includes a shaft 332 that is hollow, allowing fluid to enter pumping section 320 from the motor side. In this embodiment, pumping section 320 operates by centrifugal techniques, but pumping section 320 may utilize for other techniques (e.g., pitot-tube, with a pitot tube type impeller replacing the centrifugal impeller and an additional fluid inlet on the closed volute housing). Pumping section 320 also includes an inverted impeller 322 and a mechanical seal 324 to prevent the pumped fluid from reaching motor section 330.

Control section 340 also contains also include a mechanical seal 344 to prevent the pumped fluid from reaching motor section 330. Additionally, control section 340 includes a control board 342 upon which the controller for the pump 300′ is mounted.

FIG. 6 illustrates an example integrated pump 400 in accordance with an additional aspect of the present invention. Similar to pump 100, pump 400 includes a pumping section 420, a motor section 430, a control section 440, and an integrating housing 410. However, in this embodiment, shaft 422 of motor section 420 is hollow, allowing fluid to enter pump 400 from the motor side. Additionally, shaft 422 includes axial impeller 424 for pumping the fluid. Pump 400 may, therefore, be incorporated in-line with a process.

FIG. 6A illustrates an example integrated pump 400′ in accordance with yet another aspect of the present invention. Similar to pump 400, pump 400′ includes a pumping section 420, a motor section 430, a control section 440, and an integrating housing 410. Additionally, motor section 430 includes a shaft 432 that is hollow, allowing fluid to enter pump 400 from the motor side, and shaft 432 includes an axial impeller 434 for pumping the fluid. Pump 400 may, therefore, be incorporated in-line with a process. Pumping section 320 also includes an inverted impeller 422 and a mechanical seal 426 to prevent the pumped fluid from reaching motor section 330.

Control section 440 also includes a mechanical seal 444 to prevent the pumped fluid from reaching motor section 430. Additionally, control section 340 includes a control board 442 upon which the controller for the pump 400′ is mounted.

FIG. 7 illustrates an example integrated pump 500 in accordance with another aspect of the present invention. Similar to pump 100, pump 500 includes a motor section 520, a pumping section 530, and an integrating housing 510. The motor section 520 includes a rotor 520, a stator 524, and a hollow motor shaft 526 that serves as the pump inlet. The shaft 526 is coupled to the rotor 522, which is driven by coils 525 of the stator 524. As illustrated, the motor operates by radial flux techniques, but the motor type may be an axial flux or transverse flux type motor as well.

The pumping sectioning 530 includes a two-part pump housing 532 a-b that houses a two-part rotating fluid volume housing 534 a-b, which is coupled to the shaft 526 to be driven by the rotor 522. Pumping section 530 also includes a pitot-tube fluid pick up 536, which is stationary, to allow the rotated fluid to proceed to the outlet.

FIG. 7A illustrates an example integrated pump 500′ in accordance with another aspect of the present invention. Similar to pump 500, pump 500′ includes a motor section 520, a pumping section 530, and an integrating housing 510. The motor section 520 includes a rotor 520, a stator 524, and a hollow motor shaft 526 that serves as the pump inlet. The shaft 526 is coupled to the rotor 522, which is driven by the stator 524. As illustrated, the motor section operates by radial flux techniques, but the motor type may be an axial flux or transverse flux type motor as well. Motor section 520 also includes a mechanical seal 528 to prevent the pumped fluid from reaching the interior of the motor section 520. The mechanical seal 528 is protected by a housing 529.

The pumping sectioning 530 includes a rotating fluid volume housing 534, which is coupled to the shaft 526 to be driven by the rotor 522 of the motor 520. Pumping section 530 also includes a pitot-tube fluid pick up 536, which is stationary, to allow the rotated fluid to proceed to the outlet. Additionally, pumping section 530 includes a mechanical seal 537 and an O-ring seal to prevent the pumped fluid from escaping the pumping section.

FIG. 7B illustrates an example integrated pump 500″ in accordance with yet another aspect of the present invention. Similar to pump 500, pump 500″ includes a motor section 520, a pumping section 530′, and an integrating housing 510. The motor section 520 includes a rotor 522, a stator 524, and a hollow motor shaft 526. However, in this implementation, the shaft 526 serves as the fluid outlet. The shaft 526 is coupled to the rotor 522, which is driven by the stator 524. As illustrated, the motor operates by radial flux techniques, but the motor type may be an axial flux or transverse flux type motor as well. Motor section 520 also includes a mechanical seal 528 to prevent the pumped fluid from reaching the interior of the motor section 520. The mechanical seal 528 is protected by a housing 529.

The pumping sectioning 530′ includes a fluid volume housing 534′, which is stationary, and a pitot-tube 536′, which is coupled to the shaft 526 to be driven by the rotor 522 of the motor 520. Additionally, pumping section 530 includes a mechanical seal 537. Pumping section 530 also includes an arm 539, which balances the pitot tube. In particular implementations, arm 539 may also be a pitot tube.

A variety of integrated pump embodiments have been discussed in detail, and several others have been mentioned or suggested. Additionally, those skilled in the art will also recognize that a variety of additions, deletions, substitutions, and transformations may be made while still achieving integrated pumps. Thus, the scope of the protected subject matter should be measured by the claims, which may encompass one or more concepts of one or more embodiments. 

1. An integrated electric motor and fluid pump, comprising: a pumping section; a control section; and an motor section, the motor section comprising a stator, a rotor, and a shaft, the shaft located inside the rotor and rotated thereby; and an outer housing at least partially surrounding the motor section and coupled to and supporting the pumping section and the control section.
 2. The integrated electric motor and fluid pump of claim 1, wherein the electric motor section further comprises a bearing that supports the shaft.
 3. The integrated electric motor and fluid pump of claim 2, wherein the bearing is also configured to support the pumping section.
 4. The integrated electric motor and fluid pump of claim 1, wherein the control section includes a controller that adjusts the speed of the pump to vary with respect to accommodate and respond dynamically to the load required by the pump.
 5. The integrated electric motor and fluid pump of claim 1, wherein the housing is composed of thermoplastics.
 6. The integrated electric motor and fluid pump of claim 5, wherein the housing includes integrated non-thermoplastic elements that function as heatsink elements to allow thermal cooling of the electric motor and/or pump components.
 7. The integrated electric motor and fluid pump of claim 1, wherein the motor section uses a switched-reluctance stator.
 8. The integrated electric motor and fluid pump of claim 1, wherein the shaft comprises a hollow center to convey the fluid being pumped into the pumping section.
 9. The integrated electric motor and fluid pump of claim 7, wherein the shaft includes an integral axial flow impeller to convey the fluid being pumped to the pumping section.
 10. The integrated electric motor and fluid pump of claim 7, wherein the pumping section includes a centrifugal pump.
 11. The integrated electric motor and fluid pump of claim 7, wherein the pumping section includes a pitot-tube pump.
 12. The integrated electric motor and fluid pump of claim 11, wherein the pumping section includes a fluid volume housing that is an integral with of the shaft such that the fluid volume is rotate thereby.
 13. The integrated electric motor and fluid pump of claim 1, wherein the pumping section includes a pitot tube that is integral with the shaft such that the pitot tube is rotated thereby. 